More visual script work

-Block switches to 2d/3d editor if editing visual script
-Added cast node in flow control
-Added ability to do RPC in visual script
-Comment nodes
-Fix bug with inverted cable in connecting backwards
-Copy and paste nodes, including from different scripts

modules/gdscript/gd_script.cpp

@@ -179,6 +179,15 @@ bool GDScript::can_instance() const {
 
 }
 
+Ref<Script> GDScript::get_base_script() const {
+
+	if (_base) {
+		return Ref<GDScript>( _base );
+	} else {
+		return Ref<Script>();
+	}
+}
+
 StringName GDScript::get_instance_base_type() const {
 
 	if (native.is_valid())